California, Arizona and Nevada would cut their allocations about 20% when reservoir levels drop. But other states have their own more aggressive plan. Now the federal government has to decide how to manage the drought-plagued river.
By Rachel Becker, Cal Matters
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Bracing for an ever-growing gap between supply and demand of Colorado River water, three Southwestern states today unveiled an agreement that would cut California’s supply by about 10% in most years.
California, Nevada and Arizona submitted their plan to the federal government, which will weigh how to manage the drought-plagued river after 2026, when another historic deal expires. The decision will shape long-term management of a vital water source for 40 million people, including 30 tribal nations, and 5.5 million acres of agriculture for decades.
For more than a century, the river’s water has been allocated among seven states, tribes and Mexico through a collection of deals, acts, treaties and legal decisions known as the Law of the River. But a decades-long mega-drought, culminating in the driest 23-year period in more than a century, has shriveled the river’s already over-allocated flows.
Though water levels in Lake Mead are now the highest they’ve been in nearly three years, they remain “historically low, and long-term conservation measures will still be necessary,” the U.S. Bureau of Reclamation reported Tuesday.
California takes the biggest share of the Colorado River’s water, with a yearly allocation of 4.4 million acre-feet. And Imperial Valley growers are, by far, California’s biggest user — allocated 3.1 million acre-feet a year, or more than two-thirds of the state’s supply, to irrigate half a million acres of alfalfa, winter vegetables and other crops via the Imperial Irrigation District.
The Metropolitan Water District, which provides water for 19 million Southern Californians, is another large user, typically receiving about 1 million acre feet every year, according to Bill Hasencamp, the district’s manager of Colorado River resources.
“It’s a big change that we will have to adapt to as a state,” Hasencamp said, adding “it’s 10%, so we should be able to tighten up our belt 10%.”
In the proposal submitted today, the three states agreed to collectively cut their water use when levels dip below 69% capacity, ramping up to at least 1.5 million acre-feet a year below 58% capacity.
That’s about 17% of their total allocations, enough to supply 3.75 million Southern California households for a year. Over the past ten years, the reservoirs have largely stayed below that threshold.
If the system dips lower than 38% capacity, any additional cuts up to 3.9 million acre-feet would be shared equally between the Upper and Lower Basin states.
The three states proposed a new way to trigger the cuts — based on seven reservoirs across the basin, not just Lake Mead, Hasencamp said.
John Entsminger, general manager of the Southern Nevada Water Authority, said at a briefing today that the current system has led to suspicions of states manipulating the system. Withdrawing water from Lake Mead or holding it in Upper Basin reservoirs could result in massive changes in water releases.
“This operating regime has led to a number of conflicts between the states since it was implemented in 2007 because literally one foot of elevation difference in Lake Mead or Lake Powell can result in more or less water being released,” Entsminger said. “There were constant suspicions about states gaming the system, being able to manipulate those elevations. And we believe what we are presenting today will remove the ability for this, any even suspicion.”
“It’s a big change that we will have to adapt to as a state. It’s 10%, so we should be able to tighten up our belt 10%.”
Bill Hasencamp, Metropolitan Water district
California, with its senior rights to Colorado River water, has long been sheltered from mandatory conservation during droughts. A drought contingency plan finalized in 2019 allowed for cuts to California’s deliveries for the first time, but they have never been triggered, according to Hasencamp. Desperate for additional reductions during the most recent drought, the U.S. Bureau of Reclamation called for cuts beyond those required by the existing agreements.
Under the new proposal, Arizona would shoulder most of the burden by reducing its use about 27% in most years. Nevada would cut back by about 17%, and Mexico — if it agrees — by 250,000 acre-feet, or about 17% of the 1.5 million acre-feet it’s entitled to under an agreement with the U.S.
All seven basin states had been working together — Colorado, New Mexico, Utah and Wyoming in the Upper Basin, and Arizona, California and Nevada in the Lower. But negotiations fell apart.
Now the upper and lower states are at odds, with each submitting its own competing plan to the U.S. Bureau of Reclamation. The agency’s draft assessment of its possible approaches is expected in December.
“Ideally, the seven states would be able to come to a degree of compromise like the three Lower Basin states have. And we hope that occurs. But that requires a spirit of collaboration and compromise by all seven states… We’ve not been experiencing that lately,” said J.B. Hamby, the state’s chief negotiator as chairman of the Colorado River Board of California, and also vice president of Imperial Irrigation District’s board of directors.
Even though Arizona, Nevada and California agreed to how much each state would cut, the plan has no details about how much each water user would have to forego, or whether they would be compensated.
“Ideally, the seven states would be able to come to a degree of compromise like the three Lower Basin states have. But that requires a spirit of collaboration and compromise by all seven states.”
J.B. Hamby, Colorado River Board of California
“The first stage here is just figuring out how do we make this happen within the Lower Basin. The next step is how do you make this happen within each individual state at the user level,” Hamby said. “And then a later phase is figuring out okay, what are the resources necessary to materialize all this?”
Fewer reductions would be required in California, Arizona and Nevada with higher water levels in the reservoirs, and none would be needed if the system reaches 69% capacity. Over the past 20 years, levels have never climbed that high. Even after a wet 2023, major reservoirs are only at 43% capacity; this time last year, they were at 32%.
Mark Gold, director of water scarcity solutions with the Natural Resources Defense Council, had criticized previous, short-term agreements as modest and insufficient to protect the river’s water supplies against the ravages of climate change.
This time, he said the “Lower Basin states’ proposal includes meaningful cuts that could lead to sustainable management of the Colorado River basin.”
While it won’t be enough on its own, he said, it’s a start. The key, he said, will be getting federal agencies and the Upper Basin states on board and tackling massive evaporation losses from desert reservoirs. He said those losses should be subtracted from each state’s claim on the river.
The plan that the Bureau eventually adopts would supplant the current, short-term conservation agreements that call for cutting water use across the lower basin by about 3 million acre-feet through 2026, or about 13% of the Southwest’s supply. California already agreed to cut its water use by about 1.6 million acre feet between 2023 and 2026, or about 400,000 acre-feet a year.
The Upper Basin states of Colorado, New Mexico, Utah, and Wyoming submitted a more aggressive plan for California, Arizona and Nevada that requires cuts starting at 90% of major reservoir levels. Reductions would ramp up to 1.5 million acre feet when reservoir levels hit 70%, and up to 3.9 million acre feet if they dip below 20%.
“We can no longer accept the status quo of Colorado River operations,” Becky Mitchell, Colorado’s Commissioner to the Upper Colorado River Commission, said in a statement. “If we want to protect the system and ensure certainty for the 40 million people who rely on this water source, then we need to address the existing imbalance between supply and demand.”
But Hamby said this would place too much of a burden on the Lower Basin states and goes far beyond what they have proposed in their own plan.
“Those are pretty draconian scenarios that the Upper Basin states are suggesting, which would mean real devastation to Southern California, and trickle up throughout the rest of the state,” Hamby said.
The federal government has been paying water users for much of its cuts in water use. The Biden administration announced yesterday that it has paid about $670.2 million “and will secure more than 1.58 million acre-feet of water conservation in the Basin through 2026.”
In October, the U.S. Bureau of Reclamation announced that the states’ short-term efforts — plus recent abundant rain and snow — staved off an immediate threat to water supplies and power production, a conclusion it finalized yesterday. Yet the agency stressed the need for long-term action.
“Despite near-continuous drought-response actions in recent years, low-reservoir conditions have persisted and new infrastructure risks at Glen Canyon Dam have arisen,” the U.S. Bureau of Reclamation wrote last October. “More robust and adaptive guidelines are needed.”
